Main menu font control

I have been unable to decrease the main nav font in my template for https://www.southernlives.com. My end result will be to reduce the font so that all of these tabs are on one line and then to add a second line of tabs on top. First things first is to simply decrease the font of what I have. I have searched the forum responses and added suggested bits of code to css editor and have installed easy google font without success. Any advice appreciated.